1.View - Specifically used for displaying data model, sending command request for next action and nothing else.
2.Controller - Isolate the data request from the view; decide which datamodel should be ready and how it gets it through choosing the service in subsequent level; decide which view should be navigate to in correspondent to the command sent from view.
3.Service - Switch infrastructure strategy(utilize local dao implementation or remoting service which has implemented dao in another machine or webservice configued in a website); Manoeuvre various daos on higher level to achieve an transaction.Moreover, enforce constraints and rules.
4.Distribution Layer(Optional) - Remoting or Webservice Service interface.
5.Dao - Define various CRUD operations on Domain objects
6.ORM or DataMapper - In oo project, most data retrive from Database would be mapped to objects, ORM automatically generate sql and map data to objects , DataMapper require programmers to write sql and map the tables to objects and columns to the object properties respectively.
7Model(Entity) - The bottom level product, return to View to display,
in OO project, Model should be strictly objects.
